title: Effect of 308 nm excimer laser irradiation on retinal pigment epithelium cell viability in vitro.
abstract: BACKGROUND
  Translocation of an autologous retinal pigment epithelium (RPE) sheet under the macula is currently under investigation as a treatment for exudative AMD. Excimer laser-assisted RPE sheet translocation (EST) employs intraocular excimer ablation of excess graft choroidal tissue as a measure to enhance RPE sheet functionality. This study assessed potential adverse effects of excimer irradiation on RPE cells in vitro.
  
  
  METHODS
  Human RPE cells (ARPE-19) received 308 nm XeCl excimer laser treatment or 311-312 nm UV-B irradiation. Cell death was visualised with Trypan Blue and quantified by LDH release assay. Apoptosis was detected by DNA fragmentation assay.
  
  
  RESULTS
  Laser treatment of 0.175-0.25 J/cm(2) resulted in delayed cell death within 48 h. Time course and dose response paralleled the effect of UV-B irradiation. Cytotoxicity was mediated by apoptosis. Human choroid/Bruch membrane tissue sheets covering the cells during laser irradiation reduced cytotoxicity by 87-95%.
  
  
  CONCLUSIONS
  Cultured human RPE cells are susceptible to apoptotic cell death induced by 308 nm excimer laser irradiation. Absorption by choroid/Bruch membrane tissue can largely prevent the cytotoxic effect. In clinical application, the residual adverse effect of laser ablation on graft RPE cell viability needs to be outweighed by potential advantageous effects on graft survival and functionality to allow for a sensible application of excimer ablation in RPE translocation surgery.
authors.affiliation: Department of Ophthalmology, University of Bonn, Ernst-Abbe-Str. 2, D-53127 Bonn, Germany. krohne@uni-bonn.de
authors.forename: T U
authors.initials: TU
authors.lastname: Krohne
authors.forename: S
authors.initials: S
authors.lastname: Hunt
authors.forename: F G
authors.initials: FG
authors.lastname: Holz
mesh_terms: D016570:Bruch Membrane / Q000166:cytology; D016923:Cell Death / Q000502:physiology; D002470:Cell Survival / Q000528:radiation effects; D002478:Cells, Cultured; D002829:Choroid / Q000166:cytology; D006085:Graft Survival / Q000502:physiology; D006801:Humans; D054018:Lasers, Excimer / Q000009:adverse effects*; D008268:Macular Degeneration / Q000378:metabolism / Q000601:surgery*; D055213:Retinal Pigment Epithelium / Q000166:cytology* / Q000528:radiation effects / Q000601:surgery